You hit the nail on the head there UT.... As with every true hobby, audiophiles are on a never ending journey. Fortunately, there is also quality time with sonic bliss in between.
What about my journey? I took a brief vacation from head-fi to get to know Elise better before I report on my findings. I found out she really benefits from burn in. There is maybe 60 to 80 hours on it now and it (and/or the tubes...) has developed quite a lot. Right out of the box, I felt the lows and low-mids were a bit muddy, a bit slow. Given the sound signature of my Sennheiser HD 650's, that is not a good thing. But I am happy to report that that is gone now. The bass I get now has incredible power - no - SLAM - with speed. Early on, I did a lot of tube rolling looking for more speed in the lows - that was too early I know now. People that advised to first burn in the Elise with stock are right, I should have listened to them... Since a couple of days, I kept the C3Gs and 5998 in and gave it ample hours every day. I can't believe the extension and control I'm now getting on both ends of the spectrum. It's truly addictive....
Some other pairs I really really liked and will revisit soon:
EL3N with Visseaux 6N7G - the reversed combo is also great!
Fivre 6N7GT as powers with EL3N as drivers. In this position, the 6N7GT puts out more volume than the Visseaux 6N7G
By the way: as you can see in the pictures, the shrink tubing on the adapters doesn't move at all. And I like the look a lot more then the white marshmallows
Of course, there are not that many hours on the tubes yet but I doubt that 'creep' will turn into a problem later on.
One let down: like others have reported, my amp does not like the combination of 6N7G as drivers with 6AS7G or 5998 tubes. I have several 6N7G types and none of them works for long without severe distortion. It's not the tubes. They do function well in the back (albeit with lower volume). They do work as drivers with EL3N in the back though. EL3N to the rescue! 6SN7 in the back also works. I couldn't try the combination with 6A6 in the back yet because one of my adapters is faulty. Mrs Xu Ling has kindly shipped another.
Summarizing the above in a warning: if you don't have your Elise yet, buy only one set of 6N7G and wait until you are sure your Elise likes them... If anyone has an educated guess why some (older?) Elise amps work with them and others (newer ones?) don't please let me know!
Another thing that doesn't work for me is C3G in the back. I get quite a lot of hum them. Nevermind. Still too many combo's to try.... And too many good combo's already to bother.